Stained glass is a fragile and yet enduring Christian liturgical, contemplative and decorative treasure. In the centuries after the Norman Conquest, England’s cathedrals became vast theatres of light, their great windows designed to communicate the mysteries of salvation to all who entered. In an age when most could not read Latin or English, stained glass broadcast the Bible and the Christian story in colour. The Creation, the Genealogy of Christ, the parables of Christ, the Apocalypse, saints and martyrs and their stories — all were made visible in windows filled with deep reds, blues, yellows and grisaille or greys.